Production of enameled articles carrying a gloss and matt finish



March 5, 1935. TURK PRODUCTION OF ENAMELED ARTICLES CARRYING A GLOSS AND MATT FINISH Filed March 13. 1931 Patented Mar. 5, 1935 UNITED STATES PRODUCTION OF ENAMELED ARTICLES CARRYING A GLOSS AND MATT FINISH Richard Turk, Baltimore, Md., assignor to The Porcelain Enamel and Manufacturing Company of Baltimore, Baltimore, Md., a corporation of Maryland Application March 13,

4 Claims.

The present invention relates to the production of enameled articles and in its more specific aspect the articles are provided with artistic and realistic effects by applying thereto in combination gloss and mattfinish enamels.

The present invention isdirected to a process of producing vitreous enameled articles having a surface simulating the appearance of native rocks. Broadly, the process comprises applying to a base separately and at different portions porcelain gloss enamel and porcelain matt enamel, imparting to the so-treatedarticle a suitable motion to cause said enamels to flow together, and thereafter firing. The enamels are preferably of contrasting color, and the matt enamel may contain a substantial portion of a zinc compound.

Examples will be given showing the various artistic effects which may be produced by the present invention, but it is to be understood that these are merely illustrative and the invention is not limited thereto.

Very artistic effects may be obtained by using gloss and dull enamels in combination. In nature minerals never have a uniform gloss. In other words, in their natural form some minerals are glossy and others have a matt or dull. finish. Some of these minerals are very beautiful and serve when properly finished as very attractive building materials or as ornaments. By the proper blending of gloss and dull enamels of various colors on a suitable base, for example, a metallic base, equally attractive articles or materials result which at the same time have decided advantages over the natural products. Such effects as described may be obtained in accordance with the following: a base is properly cleaned for the application of the enamel and, if a ground coat is necessary, it is then applied. Thereafter, a gloss enamel is spattered or poured onto the surface of the base or the surface of the ground coat, the gloss enamel appearing only in small amounts at different portions of the surface. Thereafter, small amounts of a matt enamel are applied to those portions of the surface, or some of them which were not originally covered by the gloss enamel. The separate pools of dull and gloss enamel are then caused to run together and form a smooth sheet of enamel by imparting to the base a slight shaking and twisting movement.- This at the same time causes the enamels to run one intov the other, giving after firing an effect very closely resembling minerals as they naturally appear. It is of 1931, Serial No. 522,388

course obvious that gloss enamel may predominate or that dull enamel may predominate, and that the gloss enamel may be of. one color and the dull enamel of another. The figure illustrates somewhat diagrammatically an enameled article-obtained by the procedure set forth. The matt finish surface of the enameled article is represented by A, and the gloss finish enamel surface by B.

While the colors used and the proportions in which they are used have considerable effect upon the result obtained, yet upon the artistic ability of the operator depends the attractiveness of the finished article. A skilled operator can reproduce substantially at will any design simulating a rock finish, and especially a marble finish.

Heretofore designs have been obtained by blending together gloss enamels, yet the truly natural effect was never obtained because of the lack of certain dull streaks and spots, and therefore the natural material was never effectively simulated.

While the matt enamel may be produced in various ways, it is preferred that it contain a zinc compound in excess.

The following are examples of ground coats,

matt enamels and gloss enamels which may be used in carrying out the present invention.

An enamel milled by the following formula matures in two and one-half minutes at a temperature of about 1450 F. to a fine smooth glossy finish.

Parts by weight Frit 100 Clay 6 Tin oxide 6 Water a 40 The frit above set forth was produced from the following mixture:

This will produce a white, opaque frit.

If the clay is increased to 15 or 20 parts in the first formula the enamel will burn to a dull or matt finish in the same time and temperature;

Similar results may be obtained by adding, in the mill, or substituting for the clay other materials such as flint, feldspar, or in general any ingredient that increases the fusing temperature of the milled enamel. The dull finish of the resulting enamel is due to the fine particles of other refractory material that are dispersed through the enamel and prevent the soft enamel particles from fusing into a smooth glass-like surface.

Dull enamels may also be obtained by underfiring a very hard enamel. For example, an

' enamel that normally matures at 1600 F. in 2 /2 ing properties.

minutes may be fired at 1450 F. for the same time and a matt finish is obtained. Matt finishes may also be obtained by etching the gloss off of ordinary enamel, and the same result may be secured by sand blasting or grinding. Dull or matt finishes may be also produced by adding one of the enamel ingredients in excess in the compounding before smelting.

While various ingredients may be added in excess, zinc compounds have given the most satisfactory results. Therefore, the production of an enamel having a matt finish by allowing one of its ingredients to be present in excess will be illustrated by the preparation of a zinc enamel. What is here termed a zinc enamel frit may be produced by compounding the following ingredients in the proportions specified:

Parts Flint 15.0 Feldspar 38.0 Borax 5.0 Sodium nitrate 5.6 Sodium carbonate 6.2 Cryolite 8.7 Antimony oxide 2.1 Zinc oxide 38.7

The materials comprising the enamel mix are carefully weighed, mixed, and smelted together at a temperature of approximately 2000 F. until all bubbling ceases. Thereafter, the molten enamel is poured into water and broken into small particles. It is then milled in a pebble mill with approximately 6% of clay and 45% of water, this clay being added merely for its suspend- It is ground down to a thick paint-like consistency. This produces what is known as a liquid enamel.

The following illustrates the preparation of a suitable ground coat for sheet steel:

Parts Flint 19.2 Feldspar 30.9 Borax 28.8 Sodium nitrate 4.8 Sodium carbonate 6.1 Fluorspar 6.8 Cobalt oxide black) .8 Manganese dioxide 2.6

The above referred to materials are prepared in the same manner to produce a frit as outlined for the preparation of the matt finish enamel. The ground coat is milled to a fairly fine mixture in the following proportions:

Parts Ground coat frit 100 Clay 6 Borax 1 Water 45 What I claim is: 1. The process of producing vitreous enameled articles having a surface simulating the appearance of native rocks, comprising applying to a,

matt enamel, imparting to the so-treated article a suitable motion to cause the enamels to fiow together into a smooth surface, and then firing. 3. The process of producing vitreous enameled articles having a surface simulating the appearance of native rocks comprising applying to a base separately at different portions thereof vitreous gloss enamel and vitreous matt enamel, the enamels being of contrasting color, imparting'to the so-treated article a suitable motion to cause said enamels to fiow together, and then firing.

4. The process of producing vitreous enameled articles having a surface simulating the appearance of native rocks comprising applying to a base separately at different portions thereof vitreous gloss enamel and a vitreous matt enamel containing a zinc compound, imparting to the sotreated article a suitable motion to cause said enamels to flow together, and then firing.

RICHARD TURK. 

